1. Field of the Invention
The present invention relates to an endoscope system, a processor device, an operation method, and a distance measurement device for observing the inside of a subject.
2. Description of the Related Art
In the medical field, it is common to perform diagnosis using an endoscope system. The endoscope system includes a light source device that generates light for irradiating a subject, an endoscope that images the subject, and a processor device that performs processing on an image signal obtained by imaging the subject, for example.
In the case of observing the subject using the endoscope system, there is a desire to know a distance between the subject and a distal portion of the endoscope (hereinafter, referred to as an observation distance) for various reasons. For example, in the endoscope system disclosed in JP1997-294708A (JP-H09-294708A), an interferometer is provided in an endoscope in order to prevent a subject from being damaged by contact with the distal portion, and the observation distance is measured using the interferometer.